1. Field of the Invention
The present invention is generally directed toward manufacturing and testing methods and, more particularly, toward a system and method for testing an engine on a production line for oil leaks.
2. Description of Related Art
During the manufacture of an automobile engine, it is necessary to confirm that the engine's oil system does not leak. In the past, oil leak testing has been a manual operation in which an associate on the production line manually connects a flow leak tester to the engine, and the flow leak tester measures the amount of air flowing through, and out of, the oil passage. If the flow rate is greater that a predetermined limit, an alarm is sounded and the engine is sent to the repair area to be checked. Because the engine is not completely sealed during the manual leak test, some of the air flows past the piston rings, into the combustion chambers, and out the open exhaust and intake valves. The amount of air that flows past the piston rings is dependent on variables that are difficult, if not impossible, to control. For example, these variables include the amount of oil on the piston and piston rings, how long the engine has set on the production line, and the orientation of the crankshaft.
Because of these variables, the manual leak testing method requires that the alarm limits be set high to compensate for the amount of air that blows by the piston rings (hereinafter referred to as ‘blow-by’) and the fluctuation in the blow-by, due to the uncontrollable variables. Since many of the oil leaks are smaller than the blow-by, many small oil leaks cannot be detected by the manual leak testing method.
Therefore, there exists a need in the art for a system and method to more accurately and reliably detect oil leaks in an engine.